The present invention relates to pile systems and methods and, more specifically, to pile systems and methods made of plastic.
Piles are a common feature of modern construction techniques, often forming a footing for a structure, a part of or support for a retaining wall, an underground fluid flow barrier, or extending above the ground to support a structure suspended above ground.
Piles can be fabricated in many sizes and shapes and can be made of many different materials. Piles are most commonly made of steel, wood, or concrete. Wood or concrete piles most commonly take the shape of a solid rectangle or cylinder, while steel piles most commonly are manufactured in the form of a hollow cylinder. However, generally planar sheet piles made of steel, concrete, or plastic are also used to some extent.
During use, piles normally extend at least partly into the ground. Numerous techniques may be used to bury the pile in the ground. One such technique is to excavate a hole using conventional techniques, place the pile into the hole, and then backfill the hole to secure the pile in place. A more common technique is to drive the pile into the earth by applying a force to the upper end of the pile.
Pile driving systems take many forms. A simple drop hammer system raises a weighted member and drops it onto the upper end of the pile. A gear or roller drive system engages the sides of the pile to crowd the pile into the earth. A vibratory hammer system uses a pair of balanced, counter-rotating eccentric weights to create a vibratory force that drives the pile into the earth. Supported hydraulic pistons can ram the pile a relatively short distance into the earth. An auger system rotates the pile about its longitudinal axis to drill the pile into the earth. When properly configured, two or more of these techniques can be combined.
Pile driving systems are, generally speaking, faster, less expensive, and more convenient than excavating techniques. However, with certain pile shapes and materials, pile driving systems are not available.
For example, sheet pile is often used for uses such as retaining walls or underground fluid barriers. Sheet pile defines elongate upper and lower edges; applying a driving force to the upper edge to drive the lower edge into the ground can cause the sheet pile to buckle and fail if significant in-ground resistance is met. Sheet pile is thus most commonly buried in the ground using excavation and backfilling.
Conventionally, sheet pile is made of steel. More recently, sheet piles have been made of plastic. Conventional plastic sheet piles are similar in configuration to metal sheet piles; usually, two or three vertical panels are joined at vertical lines (one panel may be bent, molded, or extruded to form the vertical lines) and define first and second vertical edges. The panels are angled with respect to each other to provide additional strength. Some plastic piles further define an elongate ball and socket connection on the vertical edges that strengthens the juncture between adjacent piles.
When functioning as a pile, plastic has many desirable properties. However, plastic can be even more susceptible to buckling and failure when driven by conventional pile driving techniques.
The need thus exists for improved pile systems and more specifically to improved piles and systems and methods for driving piles.
A professional patentability search conducted on behalf of the applicant turned up the following U.S. patents.
The Breaux patent discloses an underground wall system for containing hazardous waste that uses cylindrical plastic rail members with interlocking portions that are buried in the ground. Nothing in the Breaux patent discloses, teaches, or suggests using these cylindrical members as piles that are driven into the earth with a vibratory hammer or any other type of pile driver. To the contrary, the Breaux patent describes excavating a trench around the area to be isolated, placing the cylindrical members in the trench, and then back-filling to bury the members. The Breaux patent also describes the use of a guide box to arrange the members within the trench and a system for forming a seal between adjacent members.
The Carlson and Japanese ""529 patents are similar to the Breaux patent in that they relate to containment systems. The systems described in these patents employ slotted cylindrical members. As with the Breaux system, the members are buried in a previously excavated trench. The Carlson members are apparently plastic, and the Japanese ""529 members are steel. Neither one appears to be appropriate for driving into the ground.
The Schlueter, Stevens, Hermann, Simon, Murray, Norwegian ""428, and Japanese ""015 patents all disclose or appear to disclose tubular pile system employing interlocking pile members. All of these patents appear to employ conventional elongate metal members modified to have an interlocking system for joining the members together along their edges. The patents do not relate to plastic sheet piles and/or methods for allowing plastic sheet piles to be driven using a vibratory piledriver.
The Barber patent discloses a guide sleeve for piles that is driven first and through which conventional piles are subsequently driven. The Barber patent states that the piles may be joined end to end.
The Wright et al. patent discloses a bulkhead system in which piles that form the face of the wall are connected to an anchor using horizontal tension members.
The Japanese ""917 patent discloses interlocking tubular sheet piles that are inserted into pre-bored holes.
The present invention is a modular pile system. The pile system comprises first and second cylindrical plastic pile members and a detent system. Each of the pile members has an upper end and a lower end. The detent system connects the upper end of the first pile member to the lower end of the second pile member. The detent means allow the second pile member to be displaced into a desired position relative to the first pile member but substantially prevent relative movement between the first and second pile members when the second pile member is in the desired position.
The objects of the present invention can be obtained using many different embodiments of the present invention in different configurations depending upon the end use to which the pile members are wall system formed thereby is to be put.